The use of air mattresses or beds is well known. A great many types of air mattresses are known to exist, and are used widely for recreational purposes, for example as swimming pool floats, as well as for home use as a portable mattress or guest bed.
As first developed and used, air mattresses were typically formed of a single layer or height reinforced internally by a spaced series of elongate beams, referred to by those skilled in the art as I-beams. These I-beams are typically extended in the lengthwise direction of the mattress and were secured to the top and bottom faces or panels of the mattress so that the mattress would hold its shape somewhat as a load, typically a person, was placed thereon. Although well adapted for their intended use as pool floats or as pool-side mattresses for sunning and the like, these first generation air mattresses did not perform as well in the role of bedding, a such.
Accordingly, an entire industry of manufacturing air beds or mattresses developed to meet and exploit this need. As first developed, air mattresses or beds were formed to be somewhat sturdier in construction than the pool float type of air mattress through the use of heavier gauge plastics, typically polyvinylchloride (PVC) and the like, with improved interior constructions. Examples of such a single layer or height air mattress are shown in U.S. Pat. No. 3,780,388 to Thomas et al., for an inflatable air mattress of single width, i.e., a twin mattress, as well as U.S. Pat. No. 4,371,999 to Reid. An example of a double width, i.e., a full size, single layer air mattress is shown in U.S. Pat. No. 5,960,495 to Hsu et al. Common among both of these mattress designs is the use of internal “beams” or web strips for directly tying the top face and the bottom face of the air mattress together.
As the use of air mattresses for bedding continued, the need was perceived for mattresses of greater comfort levels, which resulted in air mattresses of greater height or thickness such that air mattresses more closely resembled a box spring and mattress combination in function, and ultimately height, this type of an air mattress being known as a two layer or a double height air mattress. Examples of this type of mattress are shown in U.S. Pat. No. 4,547,919 to Wang; U.S. Pat. No. 5,598,593 to Wolfe, and U.S. Pat. No. 6,568,011 to Fisher et al., respectively. As shown in the '011 patent to Fisher et al., the double height air mattress or air bed is essentially comprised of two stacked single height air mattresses formed with a lower chamber and a separate upper chamber. This is also shown in U.S. Pat. No. 6,073,291 to Davis.
Although this type of double height air mattress construction has provided increased comfort levels over single layer or height air mattresses, problems with these known types of mattress construction remain, chief among them being the inability to internally support the mattress so that any internal beams or columns used to form the mattress extend continuously from the bottom face to the top face of the mattress for more uniformly strengthening the mattress, and for more uniformly limiting the expansion or deflection of the mattress faces during use. This is not possible with the known constructions as an intermediate sheet or layer of plastic material typically divides the two chambers or layers from one another.
Another problem that arises with the use of the known air mattresses, and especially with the double height or two layer air mattresses, is the expansion of the mattress sidewall extended between the top face and the bottom face of the mattress. As known, when a person lays on the mattress a load is introduced which increases the pressure of the air trapped within the mattress, which pressurized air acts on and seeks to expand or deflect the sidewall of the mattress. This expansion needs to be limited so that the mattress holds its shape and will support the user in a comfortable sleeping position more akin to that of a conventional coil and spring mattress.
Efforts have been made to limit the sidewall expansion of air mattresses, examples of which are reflected in U.S. Pat. Nos. 5,068,931 and 5,852,839 to Gancy, disclosing spring-like couplings extended between the top face and the bottom face, and along the sidewalls, of a conventional single height air mattress. The devices of the two Gancy patents are somewhat complicated requiring a number of discrete weld or fastening points between the faces and walls of the mattress, thus increasing the likelihood of leaks developing at these fastening points in the mattress over time. Moreover, the devices of the '931 and '839 patents do not seem well suited for use with a double height mattress where the possibility of sidewall deflection is increased due to both to the size of the mattress and the loads that will be received thereon.
Another effort to resolve the problem of bulging air mattress side walls is presented in U.S. Pat. No. 4,541,135 to Karpov, which teaches a single layer or height air mattress having an inflatable tube, a second compartment ringing the air mattress, which is itself divided into two sub-chambers. The inflatable tube of Karpov is provided to support to the side walls of the mattress, but is itself an additional air chamber, and in reality two additional air chambers, susceptible to leakage.
What is needed, therefore, but appears to be unknown or otherwise available through the art, is a double height air mattress that may use a single internal air chamber and that will permit an internal support member, or members, to continuously extend between the top and bottom faces of the mattress. Moreover, such a need exists for an improved double height air mattress better adapted for controlling or limiting the expansion or deflection of the mattress sidewall, or sidewalls, during usage.